Lúpulo japonés

Well-developed leaves with 5-9 lobes; abaxial surfaces of leaves pubescent, but not densely so; infructescence rarely longer than 2 cm, with bracts and bracteoles less than 1 cm long, and notable spinulose-ciliate Inflorescences: staminate inflorescences erect, 15–25 cm, flower anthers without glands such as; pistillate inflorescences spikes, conelike, ovoid; bracteole ovate-orbiculate, 7–10 mm, pilose, margins densely ciliate-hairy. Infructescences pendulous, green, conelike, ovoid to oblong, (1–)1.5–3(–4) cm; bracteoles without yellow glands.

Humulus japonicus is native to temperate parts of Asia (China, Japan, Korea, Taiwan and the Russian Far East) and the tropical environment of Vietnam and Laos, but has become an invasive species in North America since it was imported in the late 19th century. The plant has been immensely successful in North America, and is found throughout eastern Canada and the eastern half of the United States, and considered an invasive species. In the United States Humulus japonicus has a lateral range from Nebraska/North Dakota to Maine and a vertical range from Minnesota to Georgia. Japanese hops grow well given plentiful sunlight, moisture, and nutrient rich soil, and are most commonly found along stream banks and floodplains. Japanese hops do not grow as well in shaded areas and drier soils. In milder climates, it can survive the winter.

The plant was introduced into America in the 19th century both as an ornamental and raw ingredient for the Asian tonic. In traditional Chinese medicine this herb known as lü cao is used rather uncommonly, with supposed diuretic and heat-cooling effects. Although related to the common hop Humulus lupulus, whose cultivars are the brewer's hop used in beer production, the Japanese hop is found to be deficient in the bitter acids and essential oils used for flavoring beer, being devoid of lupulin glands (or producing very few resin glands); hence the Japanese hop is not considered viable for use in brewing.